SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9459cdcb91605e016759ef231bfbc268fefcee8ec58869e9615f498761b08df3' 
  AND token = 'AXHWFj0OfFnRf86JRIAL+cdZPtK775HPqI2h3Y3SxXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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