SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc3ed45378f50ac93c205976fe175ddf31c957bd12361a1aea6d9e479fc7506f' 
  AND token = 'HU8PLFVj7SUH3Iphnt25lHT5Iw3NmvPvUVdlWIOuTfk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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