SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '805eb5953e9f0e229c1d24da36e5500ef46efda47500cdce1691b2c9ed8a899c' 
  AND token = 'OCxKIvZPjg2rSNYtLWzYw/MNoxLEVFxHDCQfFfDPCsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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