SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'beb5292e323a79d7d1214dd35a89298e7c1c1fa81eb4cb71e375e06b66b3a01b' 
  AND token = 'sNGU4kQCTE364sXjIO3Ku+oKbdJse0s06KA5sLHH8Wo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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