SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e09266490d7960edc7e49906309c683cef5c2beea4d6c0e067d2485b4cc2d828' 
  AND token = 'o/hXS1o1UgtQ6ySzOfstrzW51zEmUnXPW0mTu71bgJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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