SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f8f0b325bcd8b6d47e11add1f164cf3d0562d470a20d6dffcc105c2e7fc4e008' 
  AND token = 'vAQcV3VCh+OQr9Oev24SKscg6As+/ZKaBixmV4IeBO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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