SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '28fe602d65644f791792726b1179d1ff439c57867060eee6b8148bc2fb6f992d' 
  AND token = 'u888zWAE6Rnp/DygJXH0eVfoHlgLgeqfmNZDgp3UOTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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