SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c973645035022994c4904b3479e5dd36b6b972e5522ea4bb2a0b624ed86b5966' 
  AND token = 'z/E1p4cFBPtxAjHrHMEF31JxJuewGBmAlqf3cgolzuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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