SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5eb3177d72959b09af5d8515cc080d888995f893bbcbb32106907e765f67698f' 
  AND token = 'e+Itd40h3FUlw3vNX2iU7X0BiHcb672j3BAcQT6dyWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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