SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84f40647b666cd311469046836a8e75945dfee28793f3a511fec128d905b5b10' 
  AND token = 'pR7qRRTh0zudG9H8LLnfrD+LNExj2bq4EROzvyoYwA4=' 
  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"
    }
  }
}