SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c76d4c3f42ccd5655b2577654a319ed787776dada7e01746d57566b287b7e2b1' 
  AND token = 'pfB1ZYIiR2tVu33c0xqvvtVffgAR4fzuMHQMtHU+Txs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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