SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1d4d6d7ffff32784110e2a9dfc47a9071dd19eddfc8b61e02976a0f44285fad' 
  AND token = 'oDyIXXbxDca4V7DRVdfs3NUjsRAjiIbXiMWj2QA8iPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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