SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6491b47bd5923a2efcc78a3a899fc62b8ce33ae3977e093c4808d2ac607a91ca' 
  AND token = '/jCRfjFsMRg5trJpOKwFkTLa49iPnSsJ+mOCPYfQZVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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