SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73fe0f3828c0b6a3386d08fdcd972be084e7edff2106d9f18712cf4509e80827' 
  AND token = '5DrwHE2ngHo18CDTQFjprid0AdJcTWn6HTerN1QsXi4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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