SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66bd6753215642f714fb209bed324f5476911f95473ca164a39dd3c92c55d60e' 
  AND token = '7Pd2BktYKuIN1bm+wHcV2Dodz3LQHupFGdibOePs92I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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