SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'bdcb6b7dcfc44404b7a1e58a0b20c66bf79d0c3443fee5e34d38bcaef2a62749' 
  AND token = 'Zz8aEAdGThsVz+0uV+hXrY17lkECMyBVzUmOg8lgx64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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