SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b984bcef7a75670473ab0b271cf078f345d75a504badecf12d7971845d8e0ec7' 
  AND token = 'o7+nc3vzVSnO4oEmrpgHnGJn+V4gYtuPdlUrSaVTWOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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