SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33d710019e0d2226074909606140a64cff5db185af7a420355718fe27deb6aa8' 
  AND token = 'H5s1JyRfiScBvwp0tDaYqsNMet+zrpA0AC6LxDjCWfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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