SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c09f3bf85853d82e4b3db4a8fa1433867335a8b49074d5e2380ed565b0f76518' 
  AND token = 'mcxdvP9XMsZjK0nkVyUsjreqx5Dfj1luq4Zyj7DG/SQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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