SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3694cfa289f37b295e39971c7bb43ce0d3579f5f7028feda6444c93aa034d2d1' 
  AND token = '9PQITbR9NB04/jubIotZr4kBmaIcXFXVJ75KwMBeq+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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