SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '357ed70e5b60829ae16ac28bc15755382b808f277fe36f8ffb383d9277e79f4a' 
  AND token = 'Mv70ST160wwC+AJrn7+fi16g2qOYS2BOoa6JPZRTNPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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