SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d643e1559ac48839cdab2e4826bfc98316664e09f069fd60e6ac032e4e29c97' 
  AND token = 'LmMsvBC0ZAmcFqWVHAj+vf9ojjqbSQsL9a0/SOgzgwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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