SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41a8634ce1c43221fbcbf025152556619c4eece57457faec1214b7153503ceb9' 
  AND token = '4QHMhHNNdgyxxAQTk+T4ArzjOt4G/dbereG/hrS5Ff8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}