SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b2500c56c78eb6592c518d2c0c821997a95d4e6b6517ec57539e29da2222275' 
  AND token = 'AEVdNwU90gtqmxW6hbt+oRYQMXKmYNHRE2292R9N3XI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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