SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de860721868dc2302b3ff96ce1889a11386ce11d3cccd4fff37068b442fc2611' 
  AND token = 'dBjMP7bkDJj3krWfISbyyJHoghhLhtu6+yrmFdPR4qU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}