SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd4b835aac4f497003b3ed493bd2dc17841e86f3fd3a695f4f1f48894181009e3' 
  AND token = '6gcEOMu+hO6Q3fJWwskIQGIjMpZsC5woSWQaSBm4//o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00073

JSON explain

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