SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dd21fc606ccd8b836038bf1b47b78e4e21e8eef20f83228b6be5ea9fd94ef323' 
  AND token = 'EkeI1qnrPKCL1EdDvn9lQSfQwmYGeUZcqw+C4kC1EVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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