SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf84b389354f2a690279437673349157beae4fe6106d68cd09d3a21bec2b12ae' 
  AND token = '8gRB+39nXgY3VYOz4H5fM0KYrHxFJ5GtY2JCTH+Dzdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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