SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10cd3fe2fe547921e15f6a0bcf30da2db0ccd970f0aeb4ee84911678dd680746' 
  AND token = 'nBOesJGOe3XMOpOalidn2zbEtNgDk2+c+io//RPzUPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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