SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eeb3462ec74ab310532d2d26b762b2c223c43ac28dac92c6fcf087134eba9943' 
  AND token = 'T0Fs9msAKsPgptelKaRK0bXL1bUfiKtBdvpnZtbG2SA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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