SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '07a21e6a9307a76bc47bd7f002e192eceb6980419047e39927ba281c2d1b4bac' 
  AND token = 'IkUWGHmFBJ2W/Piq5MtAvSFYEeZsNiCvRflgzIAJUok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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