SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a68337b7a31f6799815a55f19cffa4f991a378cb7a1621b2b91695dae6b7456a' 
  AND token = 'gCzmYzMeGnYaAHEAqfB1qQQbWkRaYRQXmcdb2p8uYfk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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