SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3971279a2fd7539471ff8e005195f50b8bce8a74db689025158f89319e7e41d8' 
  AND token = 'F1SrmNoCkzNlpSimaC77NsCXilAUKggjTIyo0OKcAIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00070

JSON explain

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