SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c2f2f673cfda1a8358e9672581d661342b4c7bd2d8919bab32238fdbacc9720' 
  AND token = 'MEasPAtRP4+d/FTUsrjMfA/3h4DTJauXeJfxNddyJjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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