SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efe481f47dd9d434e98021b2d9083199e31bf1816cd7ded1d45fef0ef338cd00' 
  AND token = 'bJjWhxQgiGVuB4ttC2yZahTGvXXRCqDx8FcsASsHsk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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