SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be5e707d6043cbcf697aca1215d1b3969dc38f4e0a41721ff30cd2ca4f5bd061' 
  AND token = 'gsNy0sGrTwUzkW4l8m88/JxQhzVvMMaDmvt/ITAm31Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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