SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6063c261bc179450631d6ff8ada39a1e56e827c7623612d93373077bb28fba34' 
  AND token = 'upib4pz4hDOJgv4oSdHLCYB0LiZUC+9VipAvO/b9+XQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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