SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1d347345f322ad64bbf6a5d8d3abaac336437bf8f627f24d49434a5b89fc375' 
  AND token = 'rYRJu9IlIVk67rqO3uDk4LYmekMmz11IqrIkwlRiIE0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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