SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e33c4a351f10b1f32f3513dd68bbedd28dacc4aecc319c14c14c3618946684ac' 
  AND token = 'RCqN4InQ2/4m/a+zm0pVw6QP6PXFYHXu5W69w/jxhV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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