SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dca2a07a42ebb1eae34c058bca85032445ee18596fc92c4dd8cc6764e3be6eda' 
  AND token = '+cQ7b6VwcqTItRdlSgETcRfEmDjdvGo4kI6028088aM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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