SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb4843c82af085627e0f60347c0524de04a45c073b49778e3ea6b3f7920c0014' 
  AND token = 'foBihYzad7FmaGqWBjZHBrice9Hl94zxPLsenY2cvmM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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