SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf6bacb38d149145985162a7e91120bf5ba93d541b8b44a12fb15459efc4280a' 
  AND token = 'q6oWCH8Mynz20tQzVAOaZWoT0erzaEMuVej7SBqdkl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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