SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b0880df6f3368784f15ac288e699e01432f395a27fd225ff8f386577d802bf4' 
  AND token = 'LGscalqPVA5unpSRFuSzBCb7MzcfWRhjWYw6+CEPDJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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