SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b236f04227790abf74dc36c0d594cf2c4eea349164d9a8c79f67c1f5cda25a2' 
  AND token = '8aPkDiJ63KbPhqC0Yk5nP/UfaJWelVf+zCkK9JtGEpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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