SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df76cf176613c82977df5031f63f55f351e04da471787f3c26446760c5cb8c24' 
  AND token = 'rj3SMhxfhIM7kUzsdpKAcDLwMv2wDgVmSzKbJE9Ljqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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