SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bb2200f8904588d1849df2a40771d476f3ca5b55be3b538520d7932a5c88fd7' 
  AND token = 'fWiQ6PgmNQDKTODfzEVtDlzpNOmwfpMz3okz2ygwAkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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