SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15137d183db7bfe646f39ef82273385917c126f9607734392a4d756c67d111db' 
  AND token = 'LpcU4ARfut8YhxIj9XaQ/+lYmLAOmGpoiqFdrulQ91Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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