SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '412cab1e22cb2193711b18e23e1a538d068e587657005fd11108f21146888d20' 
  AND token = '1AkIq9i4bdweg8xkqi/xAiN8fliHX46KAHHBkiGO29o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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