SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cb2dee62cd70a01213469028f97b25da49c52e85263de1cda73b90e8734de5d' 
  AND token = 'NEsRSjByOLfVk82lyCxgzXuVATUpKRtt14eZwOi7Y3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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