SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89a0070a49846641d0c5ee02c5857564727c2a6bd6f5af8f329173cd2888f6e5' 
  AND token = 'oK9rcBSFDYCKEpNInFhejLIgsJFoVpajfnv5oLcgnjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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