SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c97397baa88ca576e4e78b90c27a5114620f3ded41cc8dfccb63373591921a5' 
  AND token = 'REdUXGAOd1QeVyGhbBrdSwTmEh5OIohgtSjkePwCGxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}