SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2648af4bfb62170d1152394213734c3f4df959c13954ef9184a5701a5697fc6b' 
  AND token = 'TmYHuDIyL+BdiKux72tvYLks1JZgVKMLCHpRRAGRYjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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