SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ccbd094bcaff9e02d6ee51ff302e925b64cdcdee672cfc11d34194fed8ddc67' 
  AND token = '7sgzDSE8UCTe47f3dtXsapErF4llgHdujqVUOfC5a8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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