SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54001abec1f6f2305ccfcafb033dc847e156a2669682220c29b6de0dfd4e76c1' 
  AND token = 'PMFY/SOUZo3HZixeGVUhOO23N5tQ9gcr2rA/PjTuOQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}