SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c2fab23a87653298b7fd0fd20d4de50c3784b499d761099aaec789e61a605e0e' 
  AND token = 'UpABmZifrco35w3yGMq/RozoCgHhDwZCDTvWLFj0hf4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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