SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10bdbc30933c4d9c503bd399a918fef2c5bc19f5b11c2c0667823712ddc21f30' 
  AND token = '0YTz2VLu4YIrvqBqJSf2pUAvqwWyvbbmlt+TC/JET+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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