SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36cfda350aa73cb88bcdcdaaf8850a6f6677566554e09072bd54512e01961b2e' 
  AND token = 'FadxyrfhXsDor35c/3701FQfP7OeSpqDOFutNlw+RIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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