SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d66cc7d0147bb3b9a69c824c4b95cce2609d572f12ca33060b14aed88b2854f' 
  AND token = '6Rv+xLfwYKEKpHQtboZuyjXkiP1Iec85nGrHcEHI3+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}