SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c90ad297d21b6fc4274f8116e64df25ee74a059c68057bcd3e4681cdf81e571b' 
  AND token = 'iM4wYij0NtBtHz3k4fG+vcNAgkjCnXbBODXxB0+0uKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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