SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac9ee65a6b09d0c5b650900a9677f25b4c7177d13c8dc6b93f42390c078ed0ab' 
  AND token = 'KjvSNrHOSQLlPQouw2CEiLBk8tcpQnO2LeziwXe/D14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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