SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c8b42931d43b4aef19d9d427fe691a3dc56ff2ad63314487033830792ef6bb21' 
  AND token = 'a0hxJvPfMsVqB09HpKuxA6G0+Q7ftTMFzurE0fCziZ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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