SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57e6e97591884c178c6b25d9032414b6d6873944c936ea4f1ee787b86e4361b1' 
  AND token = '69hTCwzSc+84JDaedpSV0RNc5GdBBRd7dw4zic4Jo2g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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