SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e839d6ba7ace43b20b121257f9fcb622a65b037feefdcc623cd11c4b5811f688' 
  AND token = 'Y/YXux+26xZogWbA2iBQEpMJppBkT8kEk3kLkYlfNnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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