SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd517428f3506ba7cb1c82318f4e26443ccead758d52711c8c5e3e45b91c0cc09' 
  AND token = 'F3sgq2Cf1gZEwa9yjl3CS+HwaPwxhaojOmWqVgrmXYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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