SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9c2b084a23cc26c39807b379f60172e80ea71d3734455f0d53de596c72ae6b9' 
  AND token = 'RlN2WKq89zQAhsWmhCTgjx2UJMur5lykdwxejkRc5SU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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