SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43c68244e7e550043b1061b92c3f369be5230f9572349d669cc6408013394f1b' 
  AND token = 'DSbbN9HIKld4YgNjBlteF8QuhYiqaOcJBBwghw0+lZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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