SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0016ff4f725fb428d80bc2cc978e23aff0cd5903933154445cc1dd5486f50143' 
  AND token = 'hSMtMqhk4H/u5gUxVuNnXMZSzmlHvaJ+pufBH2MWkp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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