SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e37c9591407721e13136e47df9c84657308ffc628e721715ddf3edc01f9159bd' 
  AND token = 'kDkMwefiZPxEYioZGXl2bY8f+DGAgZXl4kQUWntercU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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