SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ffc780c694b308a5f8ca939cdeafbe0efdd4ccda571d809482287507b0b11b0' 
  AND token = 'N/OiYTXNzNvrsEwdeHDeuFjBIsgEzlpoHJkaUD+bS6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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